After his widely panned performance in Wednesday night's debate, a more energetic President Barack Obama unveiled some fresh material of his own, asking today where the "real Mitt Romney" went.

"When I got onto the stage, I met this very spirited fellow who claimed to be Mitt Romney," Obama said at a Denver rally. "But it couldn't have been Mitt Romney - because the real Mitt Romney has been running around the country for the last year promising $5 trillion in tax cuts that favor the wealthy. The fellow on stage last night said he didn't know anything about that."

Obama said Romney kept running from the positions he's taken over the past year.

"So here's the truth: Gov. Romney cannot pay for his $5 trillion tax plan without blowing up the deficit or sticking it to the middle class. That's the math," Obama said. "We can't afford to gut our investments in education or clean energy or research and technology. We can't afford to roll back regulations on Wall Street or on big oil companies or insurance companies.

"Now, last night, Gov. Romney ruled out raising a dime of taxes on anybody ever, no matter how much money they make," Obama said, in a misreading of Romney's actual pledge not to raise taxes in the aggregate. His tax reform plan would necessarily raise taxes on some people and lower them on others.

Obama also knocked Romney for saying he would eliminate funding for public television to cut the deficit.

"That was his answer. I mean, thank goodness somebody is finally getting tough on Big Bird," he said. "It's about time. We didn't know that Big Bird was driving the federal deficit."

"And Elmo!" yelled someone in the audience.

"Elmo, too?" Obama said.

He also dinged Romney for implying during the debate that if there are tax breaks for sending jobs overseas, he might need a new accountant.

"Now, we know for sure it was not the real Mitt Romney because he seems to be doing just fine with his current accountant," Obama said.

Obama also previewed his lines for the next debate on foreign policy.

"Now, it will be interesting to see what the guy who was playing Mitt Romney yesterday will say about foreign policy when we meet next because he said it was 'tragic' to end the war in Iraq. He won't tell us how he'll end the war in Afghanistan. And I'll use the money we're no longer spending on war to pay down our debt and to put more people back to work."

Hitting on a theme that was noticeably absent from Obama's debate rejoinders, the president today referenced Romney's videotaped comments to donors in which he dismissed the "47 percent" of Americans who don't pay income taxes. The nation won't change with "a president who writes off half the nation before he even takes office," Obama said.